Insulated twisted wire pair cables are typically used in wiring harness to provide a signal path that resistant to electromagnetic interference. Twisted wire pair cables used in automotive wire harnesses may also include an uninsulated “drain” wire and are wrapped in a conductive tape or foil that provides an electromagnetic shield. The conductive tape is then overwrapped with an insulative tape. Typically two machines are used to manufacture twisted pair wire harnesses. First wire leads are fed into a post twister machine that twists two or more wires to have a specific pitch or number of twists per unit length, e.g. twists per meter. The twisted wire pair along with the drain wire are then run through a dual taper machine, so named because it applies both the conductive tape and insulative tape to the wires at the same time. The dual taper machine spirally wraps the wires with the conductive tape and insulative tape. Using two machines to manufacture the wire harness undesirably creates in-process inventory that requires storage space and is subject to loss or damage. It is typically difficult to attach the conductive tape and the insulative tape to the twisted pair. The operator may be required to place the conductive tape and insulative tape between the twists of the wire pair and have to manually rotate the cable multiple times to ensure the wires do not rotate while initiating the taping process.
The dual taper machine typically uses feed wheels to pull the wires through the machine as the tape is applied. The pressure of the feed wheels on the wire pair provides an opportunity to damage the twisted wire pair. The operator may be required to pull the twisted pair wires though the dual taper machine before the feed wheels are engaged, providing another opportunity for damage. The drain wire is typically fed into the dual taper machine from a spool. As the wires are pulled through the dual taper machine the drain wire can tangle and become wrapped around the wire pair in such a way as to pinch through the insulation of the wire pair, causing a product failure.
Damage to the insulated twisted wire pair that occurs during the manufacturing process or prior to the manufacturing process can create a failure when the wiring harness is used in the vehicle. Therefore, a facility to electrically test the twisted pair to ensure manufacturing quality is desired.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.